I take the following article from http://www.snipercou.../HeatStress.htm
Whether you are a student at a firearms training facility, a police officer on the job or a troop in the field, keeping hydrated should be paramount on your list of preventative care and health maintenance. You can not operate if you are unconscious. Lives may depend on your ability and clear thinking. We seldom speak of heat stress here on Sniper Country and we apologize for not highlighting this less than glamorous topic. It is easy to write at length about a new and exiting piece of equipment or a new training technique, but too often we ignore the physical end of the spectrum, assuming most people know what is needed to keep them effective on the job. As the fourth of July weekend ends and my local area is coming out of a record high temperature spike, heat stress seems like a good topic to broach for our readers.
Heat Stress can be one of a series of conditions where the body is under stress from overheating. It includes heat cramps, heat exhaustion, heat rash, and heat stroke. Each produces physical symptoms that range from profuse sweating, dizziness, delirium and collapse. Heat stress comes from many sources including; high temperatures, heavy workloads, lack of proper hydration and even the type of clothing being worn.
Heat Stroke is insidious. The victim often overlooks the signs. He may assume he is feeling a little slow or sluggish simply from the heat of his environment, but with profuse sweating he may feel sufficiently cooled by the evaporation of his precious fluids. If he is not taking active measures to replace these, he will become confused or unable to concentrate. Left untended, he will experience more sever symptoms such as fainting or complete collapse. If heat signs occur in the field and you recognize them, move to the cover of a shaded area and drink water. If you recognize the symptoms in a member of your team, immediately get their attention and treat them. They may not understand what is happening to them and only feel a little off their game. Make them drink water even if they do not want it. Hydration and shade are the best and often only medicine in the field. If not taken care of the victim will soon find it difficult to breathe and will lose consciousness.
Some people are more prone to Heat Stress than others. Younger individuals and those in excellent physical condition are less likely to experience stress, at least not as quickly as other, less physically fit troops. Individuals with heart, lung or kidney disease, diabetes and those on medications are more likely to experience heat stress issues. Diet pills, sedatives, tranquilizers and CAFFEINATED drinks all accelerate the likely of heat stress, as does ALCOHOL. While you might not think a team member is on any of the above, you simply can not know. People do self-destructive things as a matter of course and if the mission is important, you’d better be aware of the possibilities. While the likelihood of a soldier in combat taking these seems slim, a police officer may have taking something listed above as a matter of course. Caffeine is an obvious villain and one accepted as a daily starter. Diet pills? You bet. Without meaning to be a chauvinist or starting a war of the sexes, women often rely on these little items without informing their husbands OR partners on the job. If you know your partner has perceived problems with his or her weight, make sure they are aware of the affects of dietary pills when the temperature rises.
You are more likely to experience heat stress when first exposed to a new environment or when your job is physically demanding. It takes time to acclimate to a hot environment and if an officer has not been spending much time out of doors in the summer heat he or she may find themselves on the back side of the power curve on their first call out in the heat wave. When temperatures approach 90 degrees F you must be especially aware. In addition to temperature an increase in humidity, a decrease in air movement and a lack of shade from direct radiant heat will all affect the potential for Heat Stress.
There are some precautions you can take to avoid becoming a victim. Learn to recognize the symptoms of Heat Stress. Pace yourself if possible. Take adequate rest periods – in shade – if the mission allows. Wear loose clothing to allow for better ventilation. And STAY HYDRATED! Drink plenty of water. In a hot environment the body requires more water than typically needed to satisfy your thirst. In other words, drink MORE than you think you need! Hydrate BEFORE the mission. Drink as much as you can hold over a period of days if possible. The standard eight glasses a day will not cut it. Top off at every opportunity before and during the mission. Make sure you take sufficient water along on the mission. When it is hot out of doors water is more important than food, so pack accordingly. Leave unessential items behind and take extra liquid.
The common forms of Heat Stress that you may experience if you do not take care are as follows:
* Heat Stroke: Heat Stroke is the most serious health problem experienced by individuals in a hot environment. It is caused by a failure of the body’s internal mechanism to regulate your core temperature. Sweating will completely stop at this stage and the body can no longer rid itself of excess heat via surface evaporation. Signs include; Mental Confusion, Delirium, Loss of Consciousness, Convulsions or even a Coma. The body temperature will often soar to 106 degrees F and above. The skin will become hot and dry. The skin will often appear to be red, mottled or even bluish. Victims of Heat Stroke will die unless treated promptly. Until a medic can tend to the victim he or she should be moved to a cool area (shade if nothing else) and they should be doused in water. Fan them vigorously to increase the cooling effect. Permanent injury will result in the brain and vital organs if heat stroke is not treated in a timely manner. Death is the ultimate end of this condition. Troops in the field are at the greatest risk from Heat Stroke since they may not be in a position to be evacuated or may be low on water. Police and civilians fare better as they are usually a dial of 911 or other emergency services away from help and can often be treated quite effectively onsite by their team mates.
* Heat Exhaustion: Heat Exhaustion results from the loss of fluid through sweating. This happens when the individual fails to take in enough liquid or salt to compensate for his environment. Unlike Heat Stroke, the individual will still sweat but he or she will experience extreme weakness or fatigue, giddiness, nausea, or headaches. Their skin will become clammy and moist to the touch. Their complexion pales or appears flush and their body temperature remains normal or slightly higher. Treatment is fairly straightforward. The victim should rest in as cool a place as possible and drink an electrolyte solution. This will restore the potassium, calcium and magnesium salts lost from sweating. Short of carrying a bottle of Gatorade into the field, just stay completely and properly hydrated to prevent this condition from affecting you. Severe cases resulting in vomiting or a loss of consciousness will require medical treatment outside the purview of this article. Again, preventative measures go a long way to assuring you will not become a victim!
* Heat Cramps: Heat cramps are a painful spasm of the muscles. They are caused when an individual drinks a large quantity of water but fails to replace the body’s salts. Tired muscles -- those being worked the most at the time -- are the most susceptible to cramps. Cramps may occur during or after the activity that prompted them. Relief may be found by drinking liquids that will replace the missing salts -- once again a sports drink is the easiest method of replenishment for those outside a combat zone. In the worse cases a medic will use an intravenous saline solution for a quick response.
* Fainting: (Heat Syncope) Fainting is most common when an individual who is not acclimatized to a hot environment is required to stand or be still for a great length of time. This is an obvious problem for someone manning a hide or observation post. A person forced to stand is far more prone (pun intended) to fainting than someone who is supine. Movement is usually all that is needed to avoid fainting, but as we know, this may not always be an option, especially for the military sniper. Victims usually recover quickly once they have fallen prone and have lain down for a short period of time.
* Heat Rash: Heat Rash oh wonderful Heat rash… I saved our favorite for last. Better known as prickly heat, this rash is the scourge of soldiers everywhere. To a soldier often forced to go days without bathing this rash could be more than a little mind altering. It may not make you physically insane, but it certainly has the ability to drive you to distraction! Sleep is a rare commodity when in the field. Every troop I have ever known has relished the few minutes of sleep he can steal in the field. There is nothing more disconcerting or annoying than suffering through heat rash when at long last your platoon sergeant tells you to unload your gear and catch some shut eye. He usually follows this statement up with “you're on watch in two hours.” Prickly heat will make damn sure you will not be well rested come the next watch. By that time you will have contemplated scraping the effected area with you knife, or worse, standing up, yelling to your enemy “here I am! Put me out of my misery!” Neither of these solutions will make you very popular with your platoon or team, so it is best to just avoid this thing altogether. Prickly Heat will occur in a hot and especially humid environment where sweat is not easily removed from the surface of the skin via evaporation. Standing sweat will seemingly attack the skin and the rash quickly results. When complicated by infection this rash can be so uncomfortable or debilitating that it becomes hard to perform your tasks. It will inhibit sleep and that in turn will affect an individual's ability to think clearly. While you can certainly function with Heat Rash, you will not be at your best and the mission may suffer. Keeping your skin dry is often problematic but it is the only way to prevent this rash. Loose clothing may help. Try to keep you chest and joint areas dry. Tight clothing like underwear briefs often exacerbate the problem, trapping moisture and abrading the affected area. Many troops go without their skivvies when in a tropical environment. Skin powder and certain medications will provide relief if not always a cure.
In summery, most heat casualties are avoidable. Common sense and an awareness of the issues are usually all it takes for an individual to keep themselves in healthy order when in the field in hot weather. A little preventive maintenance is all it takes to avoid the worst symptoms of Heat Stress. It is better to be a hound about the issue than simply ignore it or say, “it can not happen to me.” Keep hydrated, keep aware and watch your buddy.